Can Europe Help U.S. Bats?
European scientists are attacking White-nose Syndrome, the disease that has devastated bat populations throughout the northeastern United States and beyond. WNS, linked to a distinctive white fungus, threatens bats across North America, yet the fungus seems to have been reported in several European countries at least since the 1980s – without killing bats. Scientists on both sides of the Atlantic are trying to figure out what’s going on, reports German broadcaster Deutsche Welle.
The disease was discovered in 2006 in a New York State cave that was littered with hundreds of dead bats, many with a powdery white substance on their noses, Deutsche Welle reporter Nancy Allison writes. Since then, WNS has spread to nine other states and killed more than a million bats, with mortality approaching 100 percent in some hibernation caves.
In October 2008, microbiologist David Blehert of the USGS National Wildlife Health Center in Wisconsin identified the white substance as a new strain of fungus, which he dubbed “Geomyces destructans.”
Allison reports that European bats with similar white fuzz on their muzzles have been seen for decades, although the bats appeared to be healthy. As WNS spread in the United States, some bat conservationists in Europe feared they might face similar threats. Others, the reporter notes, argued that European bats soon groomed the fungus off with no ill effects.
Bat-disease specialist Gudrun Wibbelt of the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin is a key player in seeking answers to this “puzzling phenomenon,” Deutsche Welle says.
She is coordinating a study of samples from four European countries to determine whether the fungi found on six European bat species is Geomyces destructans. The only way to be certain is through genetic analysis, the broadcaster reports. Blehert sent Wibbelt his protocol for the genetic work, and she and her colleagues began sequencing the European samples.
The U.S. journal Science, meanwhile, has reported that a team led by Sébastien Puechmaille of the University of Dublin (Ireland) confirmed that two genetic markers showed that fungus found on a bat in France is, in fact, G. destructans. The journal also noted that Wibbelt has identified North American fungus in bats from three other European countries, all of them healthy. Those results have been submitted for publication.
“The most important thing to remember,” Wibbelt told Deutsche Welle, “is that there have been no mass mortalities in Europe. So if it is the same fungus, that’s actually exciting news.”
European bats may hold the key to recovering US populations, the broadcaster says. “If the fungus is native to Europe, then how local bats survived may hold lessons for the survivability of bats in the U.S.,” said biologist Paul Cryan of the U.S. Geological Survey said.
And time is short, bat expert Thomas Kunz of Boston University told Deutsche Welle. “If this continues to spread, we are talking about extinctions.”
U.S. scientists are just beginning this year’s survey of bat populations to monitor the spread of WNS, which was just reported for the first time in Tennessee. “We expect more mortality [this year],” Kunz said, “we just can't say yet how bad it will be.”
Allison notes that it is not yet proven that the fungus itself is killing the bats, although “most researchers seem to think so.” Bats hibernate to save energy during the cold winter months when insects are scarce, relying on stored fat to live until spring. Bats with WNS rouse far more often than normal, apparently because of the fungus. The constant arousals cause bats to use up fat reserves and starve to death.
The identification of G. destructans in Europe leads to several possibilities. One is that European bats have learned, perhaps painfully, to live with it: “There may have been some prehistoric time where there were more individuals of each bat species in Europe, and only the resistant forms survived a similar epidemic,” Kunz told Allison.
“The European connection is very important if … G. destructans occurs there without causing mortality,” Cryan said. “For those of us dealing with White-nose Syndrome in North America, that information would be a light on a very dark horizon.”